Evaluation of hydroxyapatite powder coated with collagen as an injectable bone substitute: Microscopic study in rabbit

New percutaneous bone filling techniques are beginning to be used by radiologists in bone tumour treatment because they are less agressive than surgery. The possibility of fostering the production of new bone using an injection method by catheter has prompted us to make pure hydroxyapatite (HA) coated with collagen (cell). The aim of this study was to assess th ree kinds of beads of 100-200 mu m size by an injectable method in the distal part of femurs in rabbit. Three implanted groups were divided randomly: HA + COLL. group (n: 19); COLL. group (n: 10); HA group (n: 9). At intervals of 2, 4 and 8 weeks after surgery, bone ingrowth was evaluated on low magnification microradiographs (x 6.3) by an image analysing computer. This study has shown that bone formation induced by collagen in its isolated form is not as good as when associated with HA granules; At 4 weeks, a significant difference was observed between the three groups, with the lowest bone formation in the COLL. group. However, the amount of bone formation was small and needs to be improved.